Can I use the same paint on my walls and doors as a want a really matt effect on both if possible?
Yes you can although there are two problems you’ll face:
1) The paint may not adhere very well to a door that has a gloss finish. You’ll need to do more preparation, ensuring the surface is fully cleaned and rubbed down. The use of an acrylic primer/undercoat will help – these are usually labelled as water-based or quick-drying in DIY stores and are all pretty much the same.
2) The paint will not be as durable or as easy to keep clean as a regular gloss paint because it hasn’t been formulated for such use. However, if you are very careful for the first few weeks you will find the paint hardens when it has fully cured and will be much less prone to damage.
Hope that helps?